SUMMARY OF THE ANATOMY OF THE EYE. 



689 



vessels. The vitreous humor is divided into compartments formed by deli- 

 cate membranes radiating from the point of penetration of the optic nerve 

 to the anterior boundary where the hyaloid membrane is in contact with the 

 capsule of the lens. In this way the humor is divided up, something like 

 the half of an orange, by about one hundred and eighty membranous pro- 

 cesses of extreme delicacy, which do not interfere with its transparency. 



SUMMARY OF THE ANATOMY OF THE GLOBE OF THE EYE. 



This summary is intended simply to indicate the relations and the physio- 

 logical importance of the various parts of the eye, in connection with Fig. 

 253. 



The eyeball is nearly spherical in its posterior five-sixths, its anterior sixth 



- ---SUPERIOR RECTUS 



CHOROID 



OPTIC NERVE 



CHOROID 



-INFERIOR RECTUS 



FIG. 253. Section of the human eye. 



being formed of the segment of a smaller sphere, which is slightly projecting. 

 It presents the following parts, indicated in the figure. 



The sclerotic ; a dense, fibrous membrane, chiefly for the protection of 

 the more delicate structures of the globe, and giving attachment to the mus- 

 cles which move the eyeball. Attached to the sclerotic are the tendons of 

 the recti and the oblique muscles. 



The cornea; a transparent structure, forming the anterior, projecting 

 sixth of the globe ; dense and resisting, allowing, however, the passage of 

 light ; covered, on its convex surface, with several layers of transparent epi- 

 thelial cells. 



The choroid coat ; lining the sclerotic and extending only as far forward 



